Pressure Systems Process Safety

image002 pTaylor & Taylor Consultants are dedicated to improving pressure systems process safety where industrial gases and cryogenic liquids are utilised. We apply our expertise competently and professionally so that clients may take the correct steps with confidence on all safety and standards aspects in the design, installation, commissioning, testing, operation and performance-based functional safety of their pressure systems processes.

We are committed to protecting employees, the public, property and the environment by advising on performance-based functional safety, engineering, leadership and management practices to prevent or mitigate catastrophic releases of pressure and industrial gases and cryogenic liquids.

image006 pTaylor & Taylor Consultants can assist clients to ensure that their pressure system or process system meets national and international design, construction and operation standards in every respect, particularly where safety is concerned.

We can discuss the options available to address standards and safety of pressure systems and process systems at any stage of a project. Most usually this engagement should be done at the design concept phase before any offers to construct are issued or accepted. If the system has already been constructed or is in operation, there could be an urgent requirement to review the pressure system and ascertain through Process Hazard Analysis (PHA), HAZOP etc. that the pressure systems and process are indeed, safe in operation and that in the event of equipment or component failure, that the system fails safe. Engaging with Taylor & Taylor Consultants is the way to be sure that a pressure systems process is safe and fit for purpose.

image008Pressure Systems Safety

Control and manage risk by engaging Taylor & Taylor Consultants to identify, control and manage risk with industrial gases, bulk tanks, multiple cylinder banks or packs and pressure systems by providing competent risk assessment, evaluation, audit and professional advice. We can advise on implementing and maintaining an effective pressure and process safety management system.

image010 pTaylor & Taylor Consultants can expertly advise on current legislation (provincial and federal, US and Canadian), Codes of Practice, properties and hazards of pressure and gases being utilised, importance of product knowledge and MSDS, oxygen deficiency hazards, localised oxygen enrichment hazards if applicable, fire and explosion hazards, risk assessment, safe systems of work, personal protective equipment, precautions, confined spaces, ventilation, forced air extraction, gas detection, monitor and alarm requirements, safe and correct use of bulk tanks, multiple cylinder banks or packs, gas manifolds and spools, configuration and methodology for automatic supply, shut off, change-over and re-supply, excess pressure relief methods and devices, liquid and gas take-offs, cryogenic pumps, cooling remediation skids, vapourisers, silencers, phase separators, safety instrumented systems and levels, safe and correct access and movement, handling and storage of gases and liquids, delivery vehicle and control on site, equipment standards and inspection procedures, pre-planned maintenance, emergency procedures, rescue and first aid.

image012 pPressure systems safety is an area often overlooked by everybody until something goes wrong. Principal causes of incidents are due to inadequate equipment and/or system design, inadequate maintenance of equipment, an unsafe system of work, operator error, inadequate training/competency assessment/supervision, inadequate and/or ineffective communication, defective installation, management-of-change failures and inadequate repairs or modifications.

The main hazards from a pressure system failure are impact from the blast of an explosion or release of compressed liquid or gas, impact from flying debris and parts of equipment that fail, contact with and/or inhalation/ingestion/asphyxiation by released liquid or gas, such as cryogenic liquid nitrogen and fire as a result of the escape of flammable liquids or gases.

All the more reason to fully understand what can go wrong, how likely it is to go wrong, how severe the consequences will be when it goes wrong and what steps are necessary to prevent or mitigate undesired consequences.

Whilst 'time lapsed' since the last pressure system safety incident is perceived by many as an achievement', the reality may be that not is all as well as it should be. Companies should know with confidence that the next incident or accident is not just around the corner, and that a pressure system failure at any time will fail safe, and won't cause fatalities or injuries, nor destroy collateral assets, property or harm the environment. An effective pressure and process safety management system will provide that assurance.

image063Investing in, and fully embracing pressure system process safety management as an essential component of the way business is done also allows companies to achieve a measurable increase in revenues and a reduction in costs. More often than not, returns can be gained through productivity increases, production cost decline, lower maintenance costs, decreased CAPEX, lower insurance premiums and more companies who want to do business.

Process Safety Management System

image022 pPressure System and Process Safety is distinctly different from Occupational Health & Safety and has a management system in its own right dedicated to prevent major incidents involving unintentional releases of hazardous pressure, gases and liquids (chemicals). Such a management system is necessary for managing operations with industrial gases and cryogenic liquids in pressure systems.

At the core of a Process Safety Management System are the commitment of leadership and management to demonstrate how the organisation will define and communicate the level of performance they are prepared to accept from the business and how they will ensure that they put in place the necessary resources to achieve the required level of performance. This will require identification and communication of KPIs, engagement with the employees and 'buy in' (accountability) from stakeholders.

image018 pThe organisation should identify and assess the risks that they need to manage in order to assure the integrity of their pressure system process operations, how they should identify the necessary control measures and how they should record and maintain the process safety knowledge that they develop from these risk identification & assessment activities.

Different categories and types of risk must be controlled through a regimented process of control measures and risk management. This will develop into an action plan of ‘what, how, who and when’ must be done and managed to eliminate or mitigate the different categories of risk that have been identified during the risk assessment process.

Process Safety Management requires constant critical review, analysis and improvement. The organisation should measure and review its performance and compliance against the target set by leadership and management, ensuring that those accountable are rewarded or disciplined accordingly for their performance. Lessons must be learned and applied to the improvement of process safety management.

Taylor & Taylor Consultants can deliver process safety management solutions that will, if implemented properly by clients, be effective in increasing not only the safety of operations, people and the environment, but also productivity, cost efficiency, quality and business continuity.

Process Safety Management Projects

image028 pAt the beginning of a new project to design, construct and operate a Pressure System Process, Taylor & Taylor Consultants can act as an independent safety consultant and competent body to advise on the physical and safety considerations that must be applied before the client begins design or offers it out to contract, and of course, we can be there at all stages thereafter to ensure all specifications and contractor offerings (bids) are compliant and safe.

We can assist to guide production of Functional Design Specifications (FDS - what a system is supposed to do and how this will be achieved, for issue to Main Contractor [s] to prepare bids). This would be a detailed description of what the process installation has to achieve and specifications of the requirements for electrical, mechanical, controls, I.T and instrumentation equipment at the intended facility. The specificprocessImageCation should include the standard requirements of 'Operational Capability' in the provision of a new system, or a modification to an existing system or facility. These requirements should be produced and adhered to for design, supply, construction, operability and compliance to existing (and expected future) International Standards, client standards and specifications and all relevant legislation.

A prospective Main Contractor(s), on receipt of a Functional Design Specification, will normally be required to inform the Client that the FDS has been interpreted, corroborated and it would be substantiated by issuing a User Requirement Statement (URS) to include broad technical details of the installation, equipment, pipework, controls, materials, methodologies etc. (what will be done, how and when). Usually, both the FDS and URS are substantial documents that require intense attention to content and context to avoid mistakes, omissions, disputes etc. The FDS is more often than not issued just once, with several alliterations of the URS possible, by mutual agreement.

Further assistance can be offered to address the key factors of a pressure system process project, such as:


the internal Project Management Team (Programme Director, Project Manager, Lead Design Engineer, HSE, Maintenance, Operations etc.) even though design, construct, commission and test may have to be contracted out


of the Project Folder and Project Management Plan


with verification and acceptance of selected Main Contractor & Project Management Team


of Change Control System & Engineering Control Memorandum protocol


and verification of Functional Design Standard (FDS) & Requirements


of Statement of Design Intent, from Main Contractor


of the pressure system process description


of the P&ID register for all versions of P&ID


of OH&E standards: pressure systems process, gas safety and Management of Major Hazards


in Process Hazard Assessment (PHA), Hazard and Operability Studies (HAZOP) during design phase


of Failure Mode Effects Analysis (FMEA) as an approach for identifying all possible failures in a design, a manufacturing or assembly process, or a product or service (determination of risk of failure, consequences and additional controls)


in Failure Mode Effects and Criticality Analysis (FMECA), to include a criticality analysis to chart the probability of failure modes against the severity of their consequences


of industrial gas supply hazard reviews: bulk tanks, multiple cylinder banks or pipeline


of Technical Reviews of whole and sub-system components and provide selection rationale


of gas calculations: methodology and rationale for determination of pipework (material, length, internal and external diameter), flow, temperature, pressure, pressure drop, vaporisation etc


of pipework-jointing methodology


of seal and gasket material and performance criteria against standards and gases


of valve type and performance criteria


rationale and methodology to be utilised for determining residual O2 levels and zones under leak and catastrophic failure conditions


rationale for determination of low O2 detector positions and the quantity required


rationale for determining volumes of other gaseous leaks, quantity and positioning of gas detectors


of Sequence Interlocking Definition Documentation (SIDD)


the system control PLC and it’s configuration


of P&ID and design, functionality, compliance with standards, legislation and FDS


marking of equipment and pipework assemblies for conformity and compliance


Design Reviews (DR), to include some or all of: a Project Concept Review (PCR), a System Requirements Review (SRR), a Project Definition Review (PDR), a System Definition Review (SDR), a Preliminary Design Review (PDR), a Critical Design Review (CDR), a Production Readiness Review (PRR), a Test Readiness Review (TRR), a System Acceptance Review (SAR), and an Operational Readiness Review (ORR)


of Assessment and Statement on how installed pipework, valves and equipment meets all applicable standards (Federal, State and International)


of all alarm conditions and actions, including for low/high O2 conditions


of Emergency Stop conditions, physical location of stop buttons. Re-start procedure and validation post emergency stop operation


of purge and pressurisation process, pressure test methodology, pressure, flow, temperature and actual results against design specification


of purge and pressurisation process under operational conditions, including post system defect rectification or ‘empty tank’ scenario


of Leak testing rationale and methodology


the Design Verification and ‘Sign Off’ process


of technical, installation, commissioning, testing, acceptance and operational documentation submission from Main Contractor


of P&ID ‘As Built’


of Acceptance Test Programme (ATP)


of Site Acceptance Test (SAT)


of Written Scheme of Examination - for initial examination, then as system ages; detailing components, item identification, safe operating limits, scheme number, date of initial exam, exam interval, physical location, inspection and test


of documented Inspection, Maintenance, Repair, Modification and Defect Rectification system


of In-service Inspection of Pressure Systems, Pipework, Pressure Relief Valves and equipment guidance


of Operating & Maintenance Manual, including configuration, long-term shutdown and start-up


of Risk Assessment for the pressure system and sub-systems


of Standard Operating Procedure (SOP)


of Safe Working Procedures (SWP)


of Line management responsibility and accountability for Safety, Training, Competency and Operations


of the Operations Authorisation Process


of complete suite of Technical files and Handover documentation


of Management of Change (MOC)

Functional Safety And Safety Instrumented Systems

image030 pSafety systems can incorporate electrical, electronic or programmable electronics that perform in such a way as to prevent dangerous failures or to control them when they arise. Taylor & Taylor Consultants can provide advice on Functional Safety, Safety Instrumented Systems and Safety Instrumented levels.

Pressure systems and processes, complex or otherwise require safety standards that are more than just prescriptive in nature where compliance can be heavily reliant on the human interface alone. Functional Safety is a performance approach for reducing risk in pressure systems and processes and is addressed by standards IEC 61508, IEC 61511and ANSI/ISA 84, all of which are for a level of safety that control systems will provide to an overall pressure system or process and generate greater confidence in safety systems and operations.

Being performance based, Functional Safety standards focus on quantitative risk reduction, life-cycle considerations and the general practices or activities that make these standards different from their predecessors. Functional Safety is descriptive of a safety system that is dependent on the correct (intelligent) functioning of the logic solver, sensors and final elements to achieve a desired risk reduction level. Functional Safety is achieved when every safety function is successfully carried out and the process risk is reduced to a pre-determined level.

image038 pTo provide effective Functional Safety, a Safety Instrumented System (SIS) should be designed to prevent or mitigate hazardous events by taking a process to a fail-safe state when predetermined conditions are not met or are violated. Associated with an SIS are safety interlock systems, emergency shutdown systems and safety shutdown systems. Whilst an SIS has one or more Safety Instrumented Functions (SIF) or loops to perform its function, the SIF loop will have a combination of logic solver(s), sensor(s) and final element(s). Each SIF within a SIS will have a Safety Instrumented Level (SIL). These SIL levels may be the same, or may differ, depending on the process and the desired outcome.

Process Hazard Assessment (PHA) And HAZOP

image036 pTaylor & Taylor Consultants can advise, lead or conduct Process Hazard Assessments and HAZOPs to identify, control and manage risk with pressure systems processes. We provide the expertise to guide clients through the PHA and HAZOP process to achieve safe, successful operations within a Process Safety Management (PSM) program.

image040 pProcess Hazard Analysis (PHA) is a set of organised and systematic assessments of the potential hazards associated with a pressure system process. A PHA provides information intended to assist an organisation in making decisions for improving operational functional safety and reducing the consequences of unwanted or unplanned releases of pressure, industrial gases and hazardous chemicals. PHAs are directed toward analysing potential causes and consequences of fires, explosions, releases of inert, toxic or flammable chemicals and major spills of hazardous chemicals, focusing on equipment, pipework, instrumentation, facilities, human actions, management, communication and external factors that might impact the process.

A variety of methodologies can be used to conduct a PHA, including but not limited to a Checklist, a 'What if' list, a 'What if/Checklist', a 'Hazard and Operability Study' (HAZOP), a 'Failure Mode and Effects Analysis' (FMEA) and a 'Failure Mode Effects and Criticality Analysis' (FMECA). PHA methods are qualitative in nature. The selection of a methodology to use depends on a number of factors, including the complexity of the process, the length of time a process has been in operation, whether or not a PHA has been conducted on the process before and, if the process is unique or industrially common. Other methods such as 'Layer of Protection Analysis' (LOPA) or 'Fault Tree Analysis' (FTA) may be used post PHA if the PHA did not reach a risk decision for a give scenario.

image044 pOSHA Process Safety Management regulations in the USA mandate the use of PHAs for the identification of risks involved in the design, operation, and modification of processes that handle highly hazardous chemicals (OSHA) 1910.119 define all 14 elements of a process safety management plan, including Process Safety Information and Process Hazard Analysis.

Hazard and Operability study (HAZOP) is a structured and systematic technique for pressure system and process examination and risk management. HAZOP is often used as a technique for identifying potential hazards in a system and identifying operability problems likely to lead to nonconforming or unwanted outcomes. HAZOP is based on an assumption that risk events are caused by deviations from design or operating intentions. Identification of deviations are facilitated by using sets of “guide words” as a systematic list of deviation perspectives. Approaching risk in this manner with HAZOP methodology provides stimulation to the imagination of team members when exploring potential deviations. As a risk assessment tool, HAZOP is often described as a brainstorming technique, a qualitative risk assessment tool and an inductive risk assessment tool, meaning that it is a risk identification approach where success relies on the ability of subject matter experts to correctly predict deviations based on past experiences and general subject matter expertise.

image004 pA HAZOP study results in knowledge, obtained by identifying potential hazards and operability problems in a structured and systematic manner, that is of great assistance in determining appropriate remedial and control measures. HAZOPs are not always appropriate in all circumstances though the cost and time investment brings important benefits that can be used to validate design, functionality, material compatibility with process chemicals and prevent operating problems, thus provide a clear return on the investment beyond the cost of hazard reduction. Additional details on the HAZOP methodology may be found within IEC International Standard 61882.

Contact Taylor & Taylor Consultants if you'd like further assistance on any aspect of pressure systems process safety.